Comment 8 for bug 707024

From what I can say, I used to occasionally see this on openSUSE 11.4 but never on Ubuntu 11.10, so it kinda seems like a bug to start with.
Based on gue5t's hypothesis, I added a variable button_pressed_handled, that is used for the return value in button_release. That feels cleaner to me than hardcoding a TRUE there. However, as I mentioned, I'm unable to reproduce the bug.